This invention relates generally to test instrument probes, and more specifically to reversible test probes and probe tips.
Test instruments, such as multimeters, voltage meters, oscilloscopes and the like, are used to measure electrical parameters in various electrical devices. FIG. 1 illustrates an exemplary test instrument 100. The test instrument 100 has a test probe 102 that is coupled to an input/output 104 of the test instrument 100. The test probe 102 has a test lead 106 having a first end 108 that is coupled to the input/output 104 of the test instrument 100 and a second end 110 that is coupled to a probe body 112. The probe body 112 includes a tip 114, which is coupled to a test point (not shown) of a device (not shown) to be measured or tested. As will be clear to a person having ordinary skill in the art, a second test probe (not shown) may be coupled to output 105.
In general, different test probe tips are used for various test applications. In fact, the International Electrotechnical Commission (IEC) under the guidance of Technical Committee (TC66) generated a safety standard for Test and Measurement Equipment related to test probes referenced as IEC-61010-031. This standard specifies requirements for test probe tips 114 for various test applications. For instance, the safety standard specifies the length of the exposed metal tip of the probe used in industrial applications, referred to as category III (CAT III) and category IV (CAT IV) installation, must be less than 4 mm in length. The probe tip for low energy applications, such as used in household applications or category II (CAT II) installations, must be less than 18 mm in length. Having a probe tip with exposed metal 18 mm in length is important because this allows users to easily insert the probe tip into a standard wall socket for quick and accurate measurement, which is not possible with a 4 mm probe tip. For industrial applications (CAT III and CAT IV) where high energy exists, a reduced probe tip of 4 mm is important to help reduce risk of arcs and arc flash hazards, which is not an issue in CAT II environments.
In the past, to accommodate the need for different length probe tips, various test probe assemblies having different probe tip lengths were used with test instruments. For instance, a user may have two sets of test probes, one probe set with probe tip lengths for testing high energy applications and another probe set with probe tip lengths for testing low energy applications. However, this resulted in the user having to manage two sets of test probes. Often test points are located in an obstructed location and having multiple probes can result in problems for a user when switching out the different probes. For instance, the user may have difficulty carrying the extra probes or the equipment may put the user in an awkward position so that it is a challenge to change out the probes. Additionally, by having separate test probes, the user may misplace, drop, or lose the probes so that the appropriate probe is not available when needed.
More recently, however, test probes have been designed with probe tips that can be removed from the probe holder or body. Thus, rather than replacing the entire probe assembly, only the probe tip needs to be replaced. Consequently, the probe tips are easier to carry since the tip is much smaller than the entire probe assembly. However, removeable probe tips still require that the user carry an extra set of probe tips for various test applications. Therefore, the removeable tips still result in the situation where the user may not have the appropriate probe tips available when needed or the user may drop or lose the tips.
There is, therefore, a need for a test probe that does not require separate probe tips to be carried for use on various test applications.